Subsections

- Library
- Description
- Dialog Box
- Default properties
- Interfacing function
- Computational function (type 2)

##
Write AU sound file

### Library

Sinks

### Description

Write an audio file in .au format from the incoming signal.

### Dialog Box

Set WRITEC block parameters |
Buffer size | 2
Swap mode 0/1 | 0

- Buffer size: data is bufferized before being written to file
- Swap mode 0/1: 0 or 1

### Default properties

- always active: no
- direct-feedthrough: yes
- zero-crossing: no
- mode: no
- number/sizes of inputs: 1 / 1
- number/sizes of outputs: 0 /
- number/sizes of activation inputs: 1 / 1
- number/sizes of activation outputs: 0 /
- continuous-time state: no
- discrete-time state: yes
- name of computational function: writeau

### Interfacing function

`scilab/macros/scicos_blocks/sinks/WRITEAU_f.sci`

### Computational function (type 2)

    #include <stdio.h>
    #include <string.h>
    #include <math.h>

    #include "../machine.h"

    extern void sciprint __PARAMS((char *fmt,...));
    void mput2  __PARAMS((FILE *fa, integer swap, double *res, integer n, char *type, integer *ierr));

    void
    writeau(flag,nevprt,t,xd,x,nx,z,nz,tvec,ntvec,rpar,nrpar,
    	       ipar,nipar,inptr,insz,nin,outptr,outsz,nout)
    integer *flag,*nevprt,*nx,*nz,*ntvec,*nrpar,ipar[],*nipar,insz[],*nin,outsz[],*nout;
    double x[],xd[],z[],tvec[],rpar[];
    double *inptr[],*outptr[],*t;
         /*
         ipar[1]   = lfil : file name length
         ipar[2:4] = fmt  : numbers type ascii code
         ipar[5]   = n : buffer length in number of records
         ipar[6]   = swap
         ipar[7:6+lfil] = character codes for file name
         */
    {
      FILE *fd;
      int n, k,/* m,*/ i, ierr;
      double *buffer,*record;
    /*  long offset;*/
      int SCALE  = 32768;
      int BIAS   =   132;
      int CLIP   = 32635;
      int OFFSET =   335;
      double y;
      int sig;
      int e;
      double f;

      --ipar;
      --z;
      fd=(FILE *)(long)z[2];
      buffer = (z+3);
      ierr=0;
      /*
        k    : record counter within the buffer
      */

      if (*flag==2&&*nevprt>0)
        { /* add a new record to the buffer */
          n    = ipar[5];
          k    = (int)z[1];
          /* copy current record to output
    	 printf("%i\n",k);*/
          record=buffer+(k-1)*(*nin);

          for (i=0;i<*nin;i++)
    	{
    	  y= *inptr[i];
    	  y=SCALE*y;
    	  if (y<0.0)
    	    {
    	      y=-y;
    	      sig=-1;
    	    }
    	  else
    	    sig=1;
    	  if(y>CLIP)
    	    y=CLIP;
    	  y=y+BIAS;
    	  f=frexp(y,&e);
    	  y=64*sig-16*e- (int) (32*f)+OFFSET;
    	  record[i] = y;
    	}
          if (k<n)
    	z[1] = z[1]+1.0;
          else {
    	mput2(fd,ipar[6],buffer,ipar[5]*(*nin),"uc",&ierr);
    	if(ierr!=0) {
    	  *flag = -3;
    	  return;
    	}
    	z[1] = 1.0;

          }

        }
      else if (*flag==4) {
        fd = fopen("/dev/audio","wb");
        if (!fd ) {
          sciprint("Could not open /dev/audio!\n");
          *flag = -3;
          return;
        }
        z[2]=(double)(long)fd;
        z[1] = 1.0;
      }
      else if (*flag==5) {
        if(z[2]==0) return;
        k    =(int) z[1];
        if (k>1) {/* flush rest of buffer */
          mput2(fd,ipar[6],buffer,(k-1)*(*nin),"uc",&ierr);
          if(ierr!=0) {
    	*flag = -3;
    	return;
          }
        }
        fclose(fd);
        z[2] = 0.0;
      }
      return;
    }